<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        body {
            background: #000;
            text-align: center
        }

        #c1 {
            background: #fff;
        }
    </style>

</head>

<body>
    <canvas id="c1" width="800" height="600">

    </canvas>
</body>
<script>
    let oC = document.getElementById('c1');
    let gd = oC.getContext('2d');       //图形上下文-绘图用的接口
    //1.矩形-路径版
    // rect (x,y,w,h)
    // gd.rect(100,100,400,300)
    // gd.fill()
    //2.矩形 直接出图
    // gd.strokeRect(100,100,400,300)
    // gd.fillRect(100,100,400,300)
</script>

</html>